Through the Scope Tension Member Release Clip

ABSTRACT

A hemostatic clip assembly for mounting on a delivery device comprises a capsule and a clip slidably mounted within the capsule so that, when the clip is drawn proximally into the capsule, arms of the clip are drawn together to a closed position, an abutting surface of at least one of the arms contacting a corresponding surface of the capsule when the clip is drawn to a predetermined position within the capsule to provide a first user feedback indicating closure of the clip in combination with a tension member connected to the clip arms and biasing the clip arms toward an open, tissue receiving configuration and a yoke slidably received within the capsule and releasably coupled to the tension member, the yoke including a ball cavity for receiving a ball connector of a control element of the delivery device to maintain the clip assembly coupled to the delivery device, wherein the control element is frangible to detach the yoke from the delivery device and to provide a second user feedback and, wherein release of the yoke from the tension member provides a third user feedback.

PRIORITY CLAIM

This application is a Continuation-in-Part of U.S. patent applicationSer. No. 10/647,512 filed on Sep. 30, 2004 entitled “Through the ScopeTension Member Release Clip.” Priority is also claimed to U.S.Provisional Patent Application Ser. No. 60/568,418 filed on May 5, 2004entitled “Through the Scope Tension Member Release Clip.” The entiredisclosures of these prior applications are considered as being part ofthe disclosure of the accompanying applications and are expresslyincorporated by reference herein.

BACKGROUND

Endoscopic procedures to treat pathologies of the gastro-intestinal(“GI”) system, the biliary tree, the vascular system and of other bodylumens are becoming increasingly common.

Hemostatic clipping tools have been inserted through endoscopes todeploy hemostatic clips which stop internal bleeding by clampingtogether the edges of a wound. Such a clipping tool, complete with clipsattached to a distal end thereof, may be inserted through an endoscopeto the location of bleeding. A clip is then remotely manipulated intoposition over the site of the bleeding, clamped over the wound anddetached from the tool.

One challenge facing the endoscope operator is to properly position thehemostatic clips over the wound to effectively stop the bleeding. If aclip is deployed improperly, additional clips may be required to stopthe bleeding, extending the time required for and the complexity of theprocedure and leaving additional medical devices within the patient. Itis also important for the device operator to be certain of the status ofdeployed clips during the deployment operation. For example, beforewithdrawing the tool from the endoscope, the operator should havepositive indication that all of the deployed clips have been fullydeployed and completely released from the tool to prevent a clip whichis clamped on tissue yet cannot be released from the tool.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a hemostatic clipassembly for mounting on a delivery device comprising a capsule and aclip slidably mounted within the capsule so that, when the clip is drawnproximally into the capsule, arms of the clip are drawn together to aclosed position, an abutting surface of at least one of the armscontacting a corresponding surface of the capsule when the clip is drawnto a predetermined position within the capsule to provide a first userfeedback indicating closure of the clip in combination with a tensionmember connected to the clip arms and biasing the clip arms toward anopen, tissue receiving configuration and a yoke slidably received withinthe capsule and releasably coupled to the tension member, the yokeincluding a ball cavity for receiving a ball connector of a controlelement of the delivery device to maintain the clip assembly coupled tothe delivery device, wherein the control element is frangible to detachthe yoke from the delivery device and to provide a second user feedbackand, wherein release of the yoke from the tension member provides athird user feedback.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a clipping device according to anembodiment of the present invention;

FIG. 1A is a detail view of an exemplary clip assembly shown in FIG. 1;

FIG. 2 is a side view of the embodiment shown in FIG. 1, with an outersheath;

FIG. 3 is a cut away side view of the shaft section according to anembodiment of the present invention;

FIG. 4 is a cross sectional view of the shaft section shown in FIG. 3;

FIG. 5 is a detail view of the distal end of the control wire accordingto an embodiment of the present invention;

FIG. 6 is a perspective view of an outer sheath according to anembodiment of the present invention;

FIG. 7 is a cross sectional exploded view of the handle of the outersheath shown in FIG. 6;

FIG. 8 is a perspective view of an outer sheath lock according to anembodiment of the present invention;

FIG. 9 is a cross sectional side view of a distal end of a clippingdevice according to an embodiment of the present invention;

FIG. 10 is a cross sectional top view of a distal end of the clippingdevice shown in FIG. 9;

FIG. 11 is a cross-sectional, perspective view of the distal end of theclipping device shown in FIG. 9;

FIG. 12 is a top view of the distal end of a device according to anembodiment of the present invention with the clip arms extendedtherefrom;

FIG. 13 is a perspective view of the device shown in FIG. 12;

FIG. 14 is a perspective view of a capsule according to an embodiment ofthe present invention;

FIG. 15 is a cross sectional side view of the of the capsule shown inFIG. 14;

FIG. 16 is a top view of the distal end of a clipping device accordingto an embodiment of the present invention;

FIG. 17 is a side view of the distal end shown in FIG. 16;

FIG. 18 is a perspective view of a clip arm according to an embodimentof the present invention;

FIG. 19 is a side view of the clip arm shown in FIG. 18;

FIG. 20 is a top view of the clip arm shown in FIG. 18;

FIG. 21 is a perspective view of a bushing according to an embodiment ofthe present invention;

FIG. 22 is a cross sectional side view of the bushing shown in FIG. 21;

FIG. 23 is a perspective view of a wire stop according to an embodimentof the present invention;

FIG. 24 is a schematic side view of a clip assembly detached from abushing, according to an embodiment of the present invention;

FIG. 25 is a side view of a tension member according to an embodiment ofthe present invention;

FIG. 26 is a top view of the tension member shown in FIG. 25;

FIG. 27 is a top view of a yoke according to an embodiment of thepresent invention;

FIG. 28 is a perspective view of the yoke shown in FIG. 27;

FIG. 29 is a top view of a yoke with a control wire according to anembodiment of the present invention;

FIG. 30 is a partially cross-sectional, side view of a differentembodiment of the present invention;

FIG. 31 is a cross sectional view of the embodiment shown in FIG. 30;

FIG. 32 is a partially cross-sectional, top view of the embodiment shownin FIG. 30;

FIG. 33 is a cross-sectional view of the embodiment shown in FIG. 32;

FIG. 34 is a perspective view of a clip capsule according to a differentembodiment of the invention;

FIG. 35 is another perspective view of the capsule shown in FIG. 34;

FIG. 36 is a side elevation view of the capsule shown in FIG. 34;

FIG. 37 is a top view of the capsule shown in FIG. 34;

FIG. 38 is a top view of a bushing according to a different embodimentof the invention;

FIG. 39 is a side view of the bushing shown in FIG. 38;

FIG. 40 is a partially cross-sectional top view of a bushing-capsuleassembly according to a different embodiment of the invention;

FIG. 41 is a cross sectional area of the assembly shown in FIG. 40;

FIG. 42 is a partially cross-sectional side view of the assembly shownin FIG. 40; and

FIG. 43 is a cross sectional view of the assembly shown in FIG. 42.

DETAILED DESCRIPTION

Hemostatic clips are used routinely to stop bleeding from openingscreated during surgery as well as wounds resulting from other trauma totissues. In the simplest form, these clips grasp the tissue surroundinga wound and bring the wound's edges together to allow natural processesto heal the wound. Endoscopic hemostatic clips are used to stop internalbleeding resulting from surgical procedures and/or tissue damage fromdisease, etc. Specialized endoscopic hemostatic clipping devices areused to bring the clips to the desired location within a patient's bodyand to position and deploy the clip at the appropriate place on thetissue. The clipping device is then withdrawn, leaving the clip withinthe patient.

Endoscopic hemostatic clipping devices are designed to reach affectedtissues deep within a patient's body, such as within the GI tract, thepulmonary system, the vascular system or within other lumens and ducts.During the procedures to treat those areas, an endoscope is generallyused to provide access to and visualization of the tissue which is to betreated. The clipping device may, for example, be introduced through aworking lumen of the endoscope. The design and construction of such a“through the scope” endoscopic hemostatic clipping device presentsseveral challenges. The endoscopic clipping device has to besufficiently small to fit in the lumen of an endoscope and, at the sametime, must be designed to provide for the positive placement andactuation of the hemostatic clip. Feedback to the operator is preferablyalso provided so that the operator will not be confused as to whetherthe hemostatic clip has been properly locked in place on the tissue andreleased from the device before the device itself is withdrawn throughthe endoscope.

FIG. 1 shows a side elevation view of a through the scope hemostaticclipping device according to an exemplary embodiment of the presentinvention. This device is a hand operated tool that is used to insert ahemostatic clip through an endoscope lumen, position the clip over awound, clamp it and deploy it over the affected tissue. The tool isfurther designed to release the hemostatic clip once it has been clampedin place, and to be withdrawn through the endoscope. To more clearlyexplain the operation and construction of the exemplary device, it maybe divided into three principal components. As shown, the hemostaticclipping device 100 comprises a handle assembly 102, a shaft section104, and a clip assembly 106. The clip assembly 106 is shown moreclearly in FIG. 1A.

The handle assembly 102 forms the component that supplies a mechanicalactuation force to deploy and clamp the clip. In this embodiment, thedevice 100 is hand operated (i.e., the user's hands provide the forcerequired to carry out all the functions related to the hemostatic clip).The handle assembly 102 may be constructed in a manner similar toconventional handle assemblies of the type generally employed inendoscopic biopsy devices or in similar applications. The handleassembly 102 allows the user to move a control wire 118 or other forcetransmission member, which extends through the shaft section 104 to theclip assembly 106 at a distal end of the device 100. The handle assembly102 comprises a handle body 108 which can be grasped by the user tostabilize the device and apply a force to it. A sliding spool 110 isconnected to control wire 118, so that the user can easily pull or pushsaid wire 118 as desired.

As shown in FIGS. 1 and 2, a sliding spool 110 is mounted on the handlebody 108 so that it can slide along a slot 116, which maintains itsposition within the handle assembly 102. Because the sliding spool 110is connected to the control wire 118, the user may manipulate thecontrol wire 118 by grasping the handle body 108 and moving the slidingspool 110 along the slot 116. A return spring 112 may be provided withinthe handle body 108 to bias the sliding spool 110, and thus the controlwire 118 toward a desired position. In the present embodiment, thesliding spool 110 is biased to the proximal position. The handleassembly 102 may also include a connection portion 114, which receivesthe control wire 118 and attaches the shaft section 104 to the handleassembly 102.

The shaft section 104 mechanically connects the handle assembly 102 tothe clip assembly 106 and, together with the clip assembly 106, isdesigned to be inserted into a lumen of an endoscope. As shown in FIGS.3 and 4, the shaft section 104 comprises an outer flexible coil 130which is designed to transmit a torque from the proximal end to thedistal end of the device 100 and to provide structural strength to theshaft section 104. The coil 130 may be a conventional coil used inbiopsy devices and may, for example, comprise a single, coiled wire. Thecoiled wire may have a round, square or a rectangular cross section, andmay be made of a biocompatible material such as, for example, stainlesssteel. Additional protective and low friction outer layers may beincluded on the shaft section 104, according to known methods ofconstruction.

The control wire 118 transmits mechanical force applied to the handle102 to the clip assembly 106. The control wire 118 has a proximal endwhich is attached to a movable part of the handle 102, such as thesliding spool 110, using known methods. Stainless steel or other highyield biocompatible materials may be used to manufacture the controlwire 118, so that the structural integrity of the assembly ismaintained. It is also important to prevent stretching of the controlwire 118 when under tension since, if the wire stretches, the handle 102will have to travel a greater distance to carry out a desired operation.As shown in FIG. 5, the distal end of the control wire 118 ends in aball 140 which is used to connect the control wire 118 to theappropriate elements of the clip assembly 106, as will be describedbelow. In this embodiment, the diameter of the control wire 118 issubstantially constant from a proximal end thereof to a proximal end ofa distal tapered section 144. The ball 140 may have a diameter which isgreater than the diameter of the control wire 118, to facilitateattachment to a yoke 204. The control wire 118 may extend the length ofthe device 100, from the yoke 204 to the sliding spool 110, and slideslongitudinally through the device 100. It may be made, for example, ofstainless steel or other biocompatible metal.

The control wire 118 may also include a reduced diameter section 142designed to fail when a predetermined tension is applied thereto throughthe handle assembly 102. The tapered section 144 may be used totransition between the main body of the control wire 118 and the reduceddiameter section 142, without steps or other discontinuities which mayconcentrate stress and make the fracture point more unpredictable. Aswill be described in greater detail below, one purpose of the reduceddiameter section 142 is to facilitate the release of a hemostatic clipfrom the hemostatic clipping device 100 once the clip has been properlydeployed. It will be apparent to those of skill in the art that thelocation of the reduced diameter section 142 along the control wire 118may be varied to take into account specific requirements of the device100.

An inner sheath 132 may be used in the construction of the shaft section104, as shown in FIGS. 3 and 4. The inner sheath 132 provides a lowfriction bearing surface disposed between the outer diameter of thecontrol wire 118, and the inner diameter of the shaft section 104. Theinner sheath 132 may be formed of a low friction material such as, forexample, Teflon™, HDPE or Polypropylene. In one exemplary embodiment,the inner sheath 132 is slidable within the shaft section 104, and thecontrol wire 118 is slidable within the inner sheath 132 forming a lowfriction system of multiple bearing surfaces. To further reducefriction, a bio-compatible lubricant may be applied to the inner andouter surfaces of the inner sheath 132, along the length of the shaftsection 104. For example, silicone lubricants may be used for thispurpose.

A slidable over-sheath 150 may be included in the design of the shaftsection 104, as shown in FIGS. 1 and 2. The over-sheath 150 is designedto protect the inner lumen of the endoscope from the metal clip assembly106 and from the metal coil 130 while the hemostatic clipping device 100passes through the endoscope's lumen. After the clipping device 100 and,more specifically, after the clip assembly 106 has passed through theendoscope, the over-sheath 150 may be withdrawn to expose the distalportion of the clipping device 100. The over-sheath 150 may be formed,for example, as a single lumen plastic extrusion element slidable overthe distal portions of the clipping device 100 to selectively cover anduncover the clip assembly 106. In one embodiment, the over-sheath 150 isformed of a low friction polymer such as, for example, Teflon™, HDPE,Polypropylene, or similar materials.

The over-sheath 150 may include a grip portion 152 and an elongated body154. The grip portion 152 is designed as a handle making it easier forthe user to slide the over-sheath 150 over the shaft of the clippingdevice 100. In one exemplary embodiment, the grip portion 152 is made ofa rubber-like material to provide a good gripping surface for the user.For example, an injection moldable polymer such as TPE may be used toconstruct the grip portion 152. The elongated body 154 may be formed asa substantially cylindrical shell surrounding the shaft of the clippingdevice 100. The elongated body 154 may be attached to the grip portion152 using conventional methods as would be understood by those skilledin the art.

As shown in FIGS. 6 and 7, an exemplary grip portion 152 comprises acentral hollow channel 160 that may be used to receive the shaft of theclipping device 100. The central hollow channel 160 is aligned with theelongated body 154 to provide a continuous channel containing the shaftof the clipping device 100. The material of the grip portion 152 mayhave a high coefficient of friction, so that an interference fit ispossible between the central hollow channel 160 and the shaft of theclipping device 100 without the use of adhesives or mechanical fasteningdevices. In one embodiment, friction bosses 158 may be provided on aninner diameter of the hollow channel 160 to provide additional frictionbetween the shaft of the clipping device 100 and the over-sheath 150assembly. The friction bosses 158 may be formed, for example, asprotrusions extending from the inner diameter of the over-sheath 150 andmay have a variety of stubby or elongated shapes. The amount of frictionbetween these two components may be balanced so that no unwantedrelative movement takes place while, at the same time, making itrelatively easy for the user to slide the over-sheath 150 proximally anddistally when necessary.

A sheath stop 156 may be provided for the clipping device 100 to preventthe over-sheath 150 from sliding away from the distal end while theclipping device 100 is inserted in the endoscope. As shown in theexemplary embodiment of FIGS. 2 and 8, the sheath stop 156 physicallyblocks the grip portion 152 from sliding proximally to prevent theover-sheath 150 from being withdrawn and exposing the clip assembly 106.The sheath stop 156 is designed to easily snap in place near theproximal end of the shaft section 104 where it can be reached andmanipulated by the operator during the surgical procedure. Once the clipassembly 106 has been inserted in the endoscope and has reached thedesired location in the patient's body, the sheath stop 156 may beremoved from the shaft section 104 so that the user can move the gripportion 152 proximally to uncover the clip assembly 106.

The connection between the sheath stop 156 and the shaft section 104 mayinclude, for example, pairs of opposing fingers 162, 164 that aredesigned to snap over the shaft section 104. The fingers 162, 164cooperate to securely and releasably hold the body of the shaft section104 therebetween. The fingers 162, 164 respectively comprise guideportions 170, 172; shaft channel portions 166, 168; and blockingportions 174, 176. Insertion of the sheath stop 156 on the elongatedbody 154 is accomplished by pressing the body of the shaft section 104between the guide portions 170, 172, to spread the fingers 162, 164 andallow further insertion of the shaft 104 between the fingers 162, 164.The guide portions 170, 172 and the blocking portions 174, 176 areshaped so that insertion of the shaft section 104 towards the channelportions 166, 168 requires less effort than moving the shaft section 104in the opposite direction.

Once the shaft section 104 has been placed within the channel portions166, 168, the fingers 162, 164 snap back to their non-spread positionand retain the shaft section 104 in place therebetween. The shaftsection 104 is removed by pulling the sheath stop 156 away from theshaft section 104. Due to the shape of the blocking portions 174, 176,removing the shaft section 104 requires the application of more forcethan does insertion thereinto. Stops 180 may also be provided on thesheath stop 156 to limit the movement of the shaft section 104 towardsthe grasping portion 161 to prevent damage to the device that may becaused by excessive spreading of the fingers 162, 164. The sheath stop156 may be formed of a resilient material, such as a polymer, and may bemanufactured by injection molding.

The clip assembly 106 is disposed at the distal end of the clippingdevice 100, and contains the mechanism that converts the proximal anddistal movement of the control wire 118 into the actions necessary todeploy and release a hemostatic clip 90. FIGS. 9, 10 and 11 show,respectively, side, top and perspective views of the distal end of theclipping device 100, including the clip assembly 106 having clips in thefolded configuration. This configuration is used, for example, to shipthe clipping device 100 and to insert the clipping device 100 throughthe lumen of an endoscope. Some of the components of the clip assembly106 include a capsule 200 which provides a structural shell for the clipassembly 106, the clip arms 208 which move between open and closedpositions, a bushing 202 attached to the coil 130, and a yoke 204connecting the control wire ball 140 and the tension member 206.

As depicted in the exemplary embodiment, the proximal end of the capsule200 slides over the distal end of the bushing 202. A locking arrangementbetween these two exemplary components is provided by capsule tabs 212,which are designed to lock into the bushing 202 so that mechanicalintegrity is temporarily maintained between the capsule 200 and thebushing 202. Within the capsule 200 are contained a yoke 204 and atension member 206 which transmit forces applied by the control wire 118to the clip arms 208. The ball 140 formed at the distal end of thecontrol wire 118 is mated to a receiving socket 210 formed at theproximal end of the yoke 204. A male C-section 214 extending from thetension member 206 is received in a corresponding female C-section 216formed in the yoke 204, so that the two components are releasablyconnected to one another, as will be described below. The clip arms 208in the closed configuration have a radius section 300 which is partiallycontained within the capsule 200 to prevent opening of the arms. Each ofthe clip arms 208 goes over the tension member 206 and has a proximalend 252 which slips under a yoke overhang 254, to further controlmovement of the arms 208.

FIGS. 12 and 13 show a top and a perspective view of one exemplaryembodiment of the clip assembly 106 in an open configuration, with theclip arms 208 in a fully open position. The open configuration isobtained when the sliding spool 110 shown in FIG. 1 is moved distally sothat the ball 140 of the control wire 118 pushes the assembly containingthe yoke 204 and the tension member 206 distally within the capsule 200.As will be described below, the distal ends of the clip arms 208 arebiased toward the open position and revert to this position wheneverthey are not constrained by the capsule 200. In the exemplaryembodiment, a maximum opening of the clip arms 208 occurs when the cliparms 208 ride over the folded distal folding tabs 220 which extend fromthe distal end of the capsule 200, as shown in FIGS. 14 and 15. In thisembodiment, the tabs 220 provide a cam surface, and the clip arms 208act as cam followers, being deflected by the tabs 220. In addition, thefolding tabs 220 may also provide a distal stop for the tension member206, to retain it within the capsule 200. Thus, by moving the slidingspool 110 distally, the user opens the clip arms 208 to prepare to grasptissue therebetween.

When the sliding spool 110 is moved proximally by the user, the assemblywithin the capsule 200 also moves proximally and the clip arms 208 arewithdrawn within the capsule 200. As the clip arms 208 move proximallywithin the capsule 200, clip stop shoulders (CSS) 222 contact a distalportion of the capsule 200, for example, the folded tabs 220. Thisinteraction of the CSS 222 with the capsule 200 provides to the user afirst tactile feedback in the form of increased resistance to movementof the sliding spool 110. This feedback gives to the operator a positiveindication that further movement of the handle control will cause thehemostatic clip 90 to be deployed from the clip assembly 106. Theoperator may then decide whether the current position of the clip 90 isacceptable or not. If the position is acceptable, the operator can fullydeploy the clip 90 by continuing to move the sliding spool 110 withincreased proximal pressure to separate the yoke 204 from the tensionmember 206. If not, the operator can move the sliding spool 110 distallyto re-open the clip arms 208 and extend them out of the capsule 200,reposition the clip 90, and repeat the above steps to close the clip 90at a more appropriate location.

When the user determines that the clipping device 100 is positionedcorrectly, the proximal pressure on the sliding spool 110 may beincreased to continue deployment of the hemostatic clip 90 from the clipassembly 106, FIGS. 16 and 17 show respectively a top and side view ofthe clipping device 100 in this condition. As the proximal tension onsliding spool 110 is increased, the control cable 118 pulls the yoke 204proximally, away from the tension member 206. The tension member 206 isfirmly attached to the clip arms 208 which are prevented from movingproximally by the interaction of the CSS 222 with the folded tabs 220.If sufficient pulling force is applied to the yoke 204, the male Csection 214 of the tension member 206 yields and loses integrity withthe female C section 216 of the yoke 204. This can occur because, in theexemplary embodiment, the tension member 206 is formed of a materialwith a lower yield strength than the material of the yoke 204.

The force required to break the tension member 206 away from the yoke204 may be tailored to achieve a desired feedback that can be perceivedby the user. The minimum force required to break the tension member 206free of the yoke 204 may be selected so that a tactile feedback is feltby the user, to prevent premature deployment of the hemostatic clip 90while a maximum force may be selected so that other components of thelinkage between the sliding spool 110 and the clip arms 208 do not failbefore the male C section 214 and the female C section 216 disconnectfrom one another. In one exemplary embodiment, the tension forcenecessary to disconnect the two components may be in the range ofapproximately 4 lbf to about 12 lbf, This range may vary depending onthe size of the device and the specific application. To obtain thisforce at the interface of the male and female C sections 214, 216 alarger force will be applied by the user at the sliding spool 110, sincefriction within the device may cause losses along the long flexibleshaft.

When the male C section 214 of tension member 206 yields, several eventstake place within the exemplary device 100 nearly simultaneously. Morespecifically, the yoke 204 is no longer constrained from movingproximally by the CSS 222 abutting the capsule 200. Thus the yoke 204travels proximally until coming to rest against a distal bushingshoulder 250. The tension member 206 is not affected by this movementsince it is no longer connected to the yoke 204. The proximal ends 252of the clip arms 208 are normally biased away from a center line of thedevice 100 and are no longer constrained by the yoke overhangs 254.Accordingly, the clip latches 302 are free to engage the latch windows304 of the capsule 200, thus maintaining the integrity of thecapsule-clip arms combination after deployment. Details of one exemplaryembodiment of the capsule 200 are shown in FIGS. 14, 15 and details ofthe clip arms 208 are shown in FIGS. 18, 19 and 20.

As the yoke 204 moves proximally to abut against the bushing 202, thecapsule tabs 306 are bent away from the centerline of the capsule 200 bythe cam surfaces of the yoke 204. As a result, the capsule tabs 306 nolonger engage the corresponding bushing undercuts 350, shown in the sideand perspective views of the bushing 202 depicted in FIGS. 21, 22. Sincethe capsule 200 and the bushing 202 (which is securely connected toshaft section 104) are no longer connected, the clip assembly 106 isprevented from being released from the shaft section 104 only by itsconnection to the ball 140 of the control wire 118. As will be describedin greater detail below, in different exemplary embodiments of thecapsule, the capsule tabs 306 may be replaced by different structures.

A further result of moving the yoke 204 against the distal bushingshoulder 250 of the bushing 202 is that the distal end of the wire stop360 (shown in FIGS. 12, 16) is placed near the proximal bushing shoulder364 (shown in FIG. 22). The flared fingers 362 located at the distal endof the wire stop 360, better shown in FIG. 23, are compressed as theypass through the central ID of the bushing 202, but return to theirnormally biased open position (shown in FIG. 23) after passing past theproximal bushing shoulder 364. Further distal movement of the slidingspool 110 is thus prevented since that movement would engage the fingers362 of the wire stop 360 with the proximal bushing shoulder 364. Thisfeature prevents the clip assembly 106 from being pushed away from thebushing 202 before the ball 140 is separated from the control wire 118,as will be described below.

The wire stop 360 comprises a tube with a first slotted and flared endattached to the control wire 118 by conventional means. As shown in FIG.23, the slots impart flexibility to the device so it can easily passthrough the central lumen of the bushing 202. Flared fingers 362 areformed by the slots, and engage the proximal bushing shoulder 364. Thewire stop 360 is made of a material that is biocompatible and that hasenough resilience so that the fingers 362 re-open after passage throughthe bushing 202. For example, stainless steel may be used for thisapplication. In different exemplary embodiments that will be describedin greater detail below, the wire stop 360 may be omitted from thedevice.

One feature of the exemplary embodiment of the invention described aboveis that the user receives both tactile and auditory feedback as the clipassembly 106 is deployed and released. The separation of the tensionmember 206 from the yoke 204 produces a small clicking noise and atactile feel that is perceptible while holding the handle assembly 102.The change in axial position of the sliding spool 110 is thus augmentedby the changes in resistance to its movement and by the clicking soundand feel through the start and stop of the movement. As a result theuser is always aware of the status of the clip assembly 106, and theinadvertent deployment of a hemostatic clip 90 in an incorrect locationis made less likely. It will be apparent to those of skill in the artthat the order of male and female connectors in the device may bereversed or changed without affecting the operation of the device.

It may be beneficial for the user to be certain that the clip assembly106 has been deployed before the rest of the clipping device 100 isremoved from the endoscope. Injury to the tissue being treated couldresult if the clipping device 100 is removed from the operative sitewhen the hemostatic clip 90 is only partially deployed. Accordingly, alarge tactile feedback may be incorporated, to augment the auditory andtactile feedback stemming from the separation of the yoke 204 from thetension member 206, FIG. 24 depicts the condition where the clipassembly 106 separates from the rest of the clipping device 100.According to the described embodiment, this second user feedback isobtained by designing the control wire 118 so that it will separate fromthe end ball 140 when a predetermined tension is applied to it. In otherwords, the ball 140 of the control wire 118 is mechanically programmedto yield and separate from the body of the control wire 118 when apre-set tension is applied thereto. The size of the reduced diametersection 142 can be selected so that, when the user continues to move thesliding spool 110 proximally as the programmed yield tension is reached,the ball 140 detaches from the tapered section 144 and provides a largetactile feedback to the operator.

When the ball 140 detaches, the sliding spool 110 bottoms out at theproximal end of the handle 108, such that a full stroke of the handleassembly 102 is reached. The tension required to cause the reduceddiameter section 142 to yield and release the ball 140 may vary over arange of values. However, for best results the force should be greaterthan the tension force required for the male C section member 214 toseparate from the yoke 204. If this condition is not satisfied, asituation may occur where the clip assembly 106 is locked in place onthe patient's tissue, but cannot be released from the clipping device100. It will be apparent that this situation should be avoided. In oneexemplary embodiment, the tension force required to separate the ball140 from the body of the control wire 118 is in the range of betweenabout 10 lbf and 20 lbf at the distal end of the control wire 118. Asdiscussed above, losses along the elongated flexible shaft may requirethe user to apply a force substantially greater than this to the handlebody 102.

Once the ball 140 has separated from the rest of the control wire 118,the user can pull the rest of the clipping device 100 from theendoscope. As this is done, the yoke 204 is retained within the capsule200 by the spring and frictional forces of various features of thecapsule 200, such as, for example, the capsule tabs 306. Prior towithdrawing the clipping device 100, the over-sheath 150 may be moveddistally by the user over the entire remaining portions of the shaftsection 104 to prevent damage to the endoscope as the clipping device100 is withdrawn therethrough. The sheath stop 156 may also be placed onthe shaft section 104 proximally of the over-sheath grip 152 to preventinadvertent sliding of the over-sheath 150 from the distal end of thedevice 100.

A more detailed description of several components of the clipping device100 follows. The clip arms 208 are shown in detail in FIGS. 18, 19 and20; the tension member 206 is shown in side and top views in FIGS. 25,26; while top and side views of the yoke 204 are shown respectively inFIGS. 27 and 28. the clip arms 208 may be formed of a biocompatiblematerial such as Nitinol, Titanium or stainless steel. Maximum springproperties may be obtained by using materials such as 400 seriesstainless or 17-7 PH. As shown, a tear drop keyway 400 is formed in theclip arm 208 to mate with a corresponding tear drop key 402 formed onthe tension member 206. This feature maintains the relative positions ofthese two components and of the yoke 204 substantially constant. Theshape of the keyways 400 may be varied. For example, the keyway 400 maybe oval or elliptical. Central portions of the clip arms 208 define aspring section 404. When the proximal ends 252 of the clip arms 208 areunder the yoke 204 overhangs 254, the clip arms 208 are allowed to pivotover the tension member 206, which in turn biases the distal ends 252towards the open configuration when no longer restrained by the capsule200. As a result, the proximal end 252 of each clip arm 208 springsupward and engages the latch windows 304 in the capsule 200.

The clip arms 208 also comprise a radius section 300 that adds strengthto the clip and reduces system friction. The radius of the radiussection 300 approximately matches the inner diameter of the capsule 200and has a smooth profile to avoid scratching the inner surface of thecapsule 200. A pre-load angle α is defined between the radius section300 and the spring section 404. The pre-load angle α determines how muchinterference (pre-load) exists between the two opposing clip arms 208 attheir distal ends when closed. The greater the pre-load angle α, thegreater the engaging force that is applied by the clip arms 208.However, this condition also causes the greatest system friction whenthe hemostatic clip 90 is closed. The clip arms 208 also compriseinterlocking teeth 408 disposed at their distal ends. In the exemplaryembodiment, the teeth 408 are identical so that the arms may beinterchangeable and will mesh smoothly with the set facing them. Theteeth 408 are disposed at a nose angle β which may be betweenapproximately 90 and 135 degrees, but in other applications may begreater or lesser than the described range.

One exemplary embodiment of the capsule 200 is shown in detail in FIGS.14 and 15. The device comprises alignment keyways 500 that are designedto mate with corresponding features on the bushing 202 to rotationallyalign the two components. In this exemplary embodiment, the capsule tabs306 may be bent towards the centerline of the capsule 200 to engage thebushing undercuts 350. The engagement maintains the integrity betweenthe capsule assembly 200 and the rest of the clipping device 100 untilthe yoke 204 is pulled into the distal bushing shoulder. the capsuleoverhangs 502 provide added clamping strength to the deployed clip arms208. This is achieved by reducing the length of the portion of each cliparm 208 that is not supported by a portion of the capsule 200. Thisfeature does not affect the amount of tissue that may be captured by theclip arms 208 since the capsule overhangs 502 extend on a planesubstantially parallel to the plane of the clip arms 208.

Additional features of the capsule 200 include an assembly aid portwhich may be used to assist in aligning the components of the clipassembly 106. Bending aids 506 facilitate a smooth bend when the distalfolding tabs 220 are bent inward, as described above. The bending aids506, as shown, are holes aligned with the folding line of the tabs 220,but may also include a crease, a linear indentation, or other type ofstress concentrator. The capsule 200 may be formed from any of a varietyof biocompatible materials. For example, stainless steel, Titanium orNitinol or any combination thereof may be used. High strength polymerslike PEEK™ or Ultem™ may also be used to form the capsule 200, with aheat set treatment being used to adjust positionable elements.

A different exemplary embodiment of the present invention is shown inFIGS. 30-33. In this embodiment, several features of the clip capsuleand of the control wire actuation mechanism are modified to furtherfacilitate the release of the clips from the delivery mechanism. Asindicated above, it is important to ensure that the clip completelyseparates from the control wire after deployment to prevent a situationwhere the clip is clamped to the patient's tissue, but cannot bereleased from the deployment mechanism. Accordingly, the exemplaryembodiment shown in FIGS. 30-33 incorporates design features whichreduce mechanical side loads between the clip capsule and the bushing,and facilitate a smoother and more certain disengagement of the clip.

More specifically, the present exemplary embodiment incorporates aninterface portion 816 of the clip capsule 804 that is axially shorterthan this portion in the above-described embodiments. For example, theinterface portion 816 may up to 60% shorter in this embodiment than inthe above-described embodiments. The interface portion 816 is adapted toreleasably connect with the bushing 806 to temporarily providestructural strength to the assembly. The exemplary embodiment alsoincorporates a different distal end of the control wire 810, which canbe used to help separate the clip 802 and capsule 804 from the bushing806.

FIGS. 34-37 show in greater detail the capsule 804 according to theexemplary embodiment also shown in FIGS. 30-33. FIGS. 38 and 39 show thecorresponding bushing 806, which is adapted to cooperate with thecapsule 804 to provide a smoother separation of the clip 802 from thedelivery mechanism. Several features of the present exemplary capsule804 are similar to features of the embodiments described above and carryout the same functions. For example, the key ways 820 are designed tocooperate with features 822 of the bushing 806 to rotationally align thetwo components. The latch windows 824 also perform the same function asdescribed above with respect to other embodiments and cooperate withproximal ends of the clips 802.

One feature of the present embodiment is a shortened interface portion816 which comprises a different releasable locking mechanism to connectthe capsule 804 to the bushing 806. In this embodiment, an “A” frame tab830 is designed to cooperate with bushing hooks 832 to temporarilymaintain the capsule 804 and the bushing 806 attached to one another.FIGS. 40-43 show additional views of the capsule 804 while it isconnected to the bushing 806. During assembly of the delivery device,the two components are attached by moving the capsule 804 over thebushing 806 and then bending the “A” frame tabs 830 into the bushinghooks 832. The inside distal edge 834 of each “A” frame tab 830 ispushed down when joining the two components and locks behind the bushinghooks 832.

As a clip 802 is deployed to clamp tissue and is then released from thedeployment device 800, the “A” frame tabs 830 disengage from the hooks832 of the bushing 806 after the tension member 814 has been broken andthe cam surfaces of the yoke engage the “A” frame tabs 830 as describedabove. The release sequence is accomplished through movement of theinternal components within the capsule 804 in response to movement ofthe sliding spool 110 and the handle 108 (FIG. 2), as described abovewith reference to the previous exemplary embodiments of the device.

A second feature included in this embodiment of the clip delivery device800 comprises a control wire 810 and a hypo tube 900, as shown in FIGS.30-33. In the present exemplary embodiment, no wire stop is included andthe control wire 810 may be used to push the clip 802 away from the clipdelivery device 800 after deployment of the clip 802 therefrom. Thisadditional function of the control wire 810 may be utilized after thecontrol wire ball 902 has separated from the control wire 810, forexample by programmed failure of the reduced diameter section 904. Usingthe control wire 810 to push the deployed clip 802 provides additionalassurance that, when the clip 802 is clamped to the patient's tissue, itwill be completely released from the clip delivery device 800.

According to the exemplary embodiment shown herein, after failure of thetension member 814 and before the control wire 810 is severed, if a userpushes the control wire 810 distally in an attempt to re-open the clip802, the clip 802 will remain coupled to the tissue while bound to thecontrol wire 810. At this point, due to the shorter longitudinal lengthof the clip capsule 804, the yoke 812 may be drawn out of the proximalend of the capsule 804 by proximal movement of the control wire 810. Thebushing 806 may then be moved distally as the yoke 812 is drawnproximally to draw the proximal tapered end of the yoke 812 into thedistal opening in the bushing 806. The proximal tapered end of the yoke812 allows the yoke 812 to be realigned with the bushing 806 as the yokemay have rotated about the control wire ball 902. After the yoke 812 hasbeen re-aligned with the bushing 806, the control wire 810 may be drawnfurther proximally to separate the control wire ball 902 from theproximal portion of the control wire 810 to completely release the clip802.

One mode of operation of the exemplary embodiment of the clip releasedevice 800 is described with reference to FIGS. 30-33, and alsoreferring back to FIGS. 1 and 2. After the reduced diameter section 904has yielded and the control wire 810 has been separated from the controlwire ball 902, the sliding spool 110 is advanced distally by the userrelative to the handle 108 so that the distal (separated) end of thecontrol wire 810 pushes the clip 802 distally away from the clipdelivery device 800, providing a further assurance that the clip 802 hascompletely separated from the delivery device 800. The user may thensafely remove the delivery device 800.

After the reduced diameter section 904 has yielded, the distal end ofthe control wire 810 may be jagged or sharp. To limit the possibility ofinjury from the sharp end of the control wire 810, a protective shroud,e.g., the hypo tube 900, is placed around the distal portion of thecontrol wire 810. For example, the hypo tube 900 may be crimped onto thecontrol wire 810, causing both to move together longitudinally in andout of the catheter. It will be apparent to those of skill in the artthat other methods of attaching the hypo tube 900 to the control wire810 may be used without departing from the scope of the invention. Thehypo tube 900 placed around the sharp end of control wire 810 acts as ablunt surface to minimize trauma to tissue against which the controlwire 810 may be pushed. In addition, the hypo tube 90 stiffens thereduced diameter section of the control wire 810 to aid the reduceddiameter section in resisting buckling when subjected to compression asthe control wire 810 is moved distally.

In the present exemplary embodiment, the control wire 810 is free tomove longitudinally along the clip delivery device 800. Accordingly,various internal passages of the delivery device 800 are sized toprevent interference with the movement of the control wire 810. Forexample, an inner diameter of the bushing shoulders 906 may be such thatthe hypo tube 900 can pass therethrough without catching the lip of thebushing shoulders 906. This feature further facilitates longitudinalmovement of the control wire 810 and its use to push deployed clips 802longitudinally away from the deployment device 800.

The exemplary embodiment of the clip delivery device 800 described abovethus promotes a more positive and smooth separation of the clip 802after it has clamped on the target tissue and before the delivery device800 is withdrawn from the patient's body. A clip capsule 804 having ashorter longitudinal length and “A” frame locking tabs may promote asmoother separation of the capsule 804 from the bushing 806, by reducingthe side loads that may exist during deployment and using the controlwire 810 to push the clip 802 out of delivery device after clamping tothe target tissue provides a further assurance of positive release.

FIGS. 25 and 26 depict additional details of the tension member 206. Asshown, tear drop keys 402 are designed to engage the tear drop keyways400 of the clip arms 208, as described above. Clip follower planes 508are shaped to form a fulcrum which allows the clip arms 208 to rockbetween the open and closed configurations. The tension member 206comprises a distal stop face 510 which abuts the distal folding tabs 220of the capsule 200 to stop the distal motion of the capsule assembly106. In general, all surfaces and edges of the tension member 206 thatare in contact with the inner surfaces of the capsule 200 preferablyhave a radius substantially similar to an inner radius of the capsule200 to provide a sliding fit therein. The tension member 206 may beformed of a biocompatible polymer, monomer or thermoset. The type ofmechanism selected to release the tension member 206 from the yoke 204may determine the type of material used since a release due to fractureof the male C section 214 requires a relatively brittle material whilerelease due to yielding without fracture calls for a softer material.

Additional details of the yoke 204 are shown in FIGS. 27-29. When thecontrol wire 118 is seated in the yoke 204, it is desirable to ensurethat it cannot inadvertently be removed from the control wire slot 600.Accordingly, in the present embodiment the ball cavity 602 has adiameter sufficiently large to allow the ball 140 to pass therethroughwhile the wire cavity 604 is large enough to allow the control wire 118to pass therethrough, but not large enough to allow the ball 140 passtherethrough. To assemble the control wire 118 with the yoke 204according to the exemplary embodiment, the proximal end of wire 140 isinserted into the ball cavity 602 until the ball bottoms out, and thenthe control wire 118 is rotated until it is seated in the control wirecavity 604, thus constraining further movement of the ball 140.According to the present embodiment, the yoke 204 may be made of abiocompatible metal such as stainless steel or a high strength polymersuch as Ultem™.

According to embodiments of the present invention, the clipping device100 may be scaled to fit the requirements of different surgicalprocedures. In one exemplary embodiment, the clipping device 100 may besized to fit through an endoscope having a working channel diameter ofapproximately 0.110 inches. The exemplary bushing may have a length ofabout 0.22 inches and an OD of approximately 0.085 inches. The capsulemay have a length of about 0.5 inches, an OD of about 0.085 inches, anda wall thickness of about 0.003 inches. When assembled, the rigid lengthof the capsule 200 and the bushing 202 is approximately 0.625 inches.This length is important because if it is too great, the assembly willnot pass through the bends of the flexible endoscope. In the exemplaryclipping device, the outer sheath may have an ID of approximately 0.088inches and an OD of about 0.102 inches. The overall length of theclipping device may be approximately 160 inches, while the tissuegrasping portion of the clip arms 208 may be approximately 0.4 incheslong.

Several aspects of the present invention are described below. In oneaspect, the present invention is directed to an apparatus for deploymentof a hemostatic clip comprising a handle assembly, a shaft connected toa distal portion of the handle assembly, a clip assembly releasablycoupled to a distal portion of the shaft, the clip assembly includingclip arms and a capsule cooperating with the clip arms to provide afirst user feedback indicating a decision configuration of the clipassembly, and a control wire including a ball connector, the controlwire extending from the handle assembly and coupled to the clip assemblyby the ball connector to maintain the clip assembly coupled to theshaft, wherein the ball connector is detachable from the clip assemblyto provide a second user feedback indicating separation of the clipassembly from the shaft.

The apparatus further includes an over sheath movable between a firstposition covering the shaft and the clip assembly and a second positionuncovering the clip assembly. The over sheath has an over sheath stopengageable on the shaft to prevent movement of the over sheath to thesecond position.

The clip arms further comprise stop shoulders engaging a distal end ofthe capsule to provide the first user feedback during proximal movementof the control wire. The decision configuration indicates a position ofthe control wire beyond which further proximal movement of the controlwire precludes return of the clip arms to an open configuration by areversed movement of the control wire.

The capsule of the apparatus for deployment of a hemostatic clip furthercomprises a yoke including a ball cavity and being slidable within thecapsule, the yoke receiving the ball connector in the ball cavity, and atension member releasably connected to the yoke, the tension memberbeing connected to the clip arms and biasing the clip arms toward anopen configuration, wherein the tension member releases from the yokewhen the control wire is moved proximally beyond the position at whichthe first user feedback is provided. The tension member and the yoke arereleasably connected to one another by a male C section member and afemale C section member. Separation of the yoke and tension memberoccurs by one of fracture and deformation of the male C section member.

In the apparatus for deployment of a hemostatic clip, separation of theyoke and tension member occurs when a tension on the control wiretension is at least a predetermined separation tension. For example, theseparation tension is at least approximately 4 lbf, or alternatively maybe less than approximately 12 lbf. The separation of the yoke andtension member locks the clip arms in a closed configuration by slidingthe tension member and the clip arms proximally within the capsule.Separation of the yoke and tension member also allows proximal movementof the yoke to release the capsule from a bushing of the shaft. Distalmovement of the control wire, before separation of the yoke from thetension member, slides the clip arms distally out of the capsule into anopen configuration.

In the apparatus for deployment of a hemostatic clip, the first feedbackincludes a tactile and aural feedback. The control wire furthercomprises a reduced diameter section adjacent to the ball connector, thereduced diameter section yielding when a tension in the control wirereaches a predetermined yield tension. The yield tension is greater thanthe separation tension, and may be between approximately 10 lbf and 20lbf.

In another aspect, the invention is directed to a clip deploymentapparatus insertable to locations within a body through an endoscope.The apparatus includes an elongated member extending from a proximal endto a distal end, a control wire extending from the proximal end of theelongated member to the distal end thereof, a bushing coupled to thedistal end of the elongated member, and a capsule releasably connectedto the bushing. The apparatus further includes clip arms slidable withinthe capsule between a distal open configuration and a proximal closedconfiguration, a tension member slidable with the clip arms, the tensionmember biasing the clip arms toward the open configuration, and a yokeslidable within the capsule, a first end of the yoke being releasablyconnected to the tension member and a second end of the yoke beingconnected to the control wire, wherein distal movement of the controlwire slides the clip arms into the open configuration, and proximalmovement of the control wire slides the clip arms into the closedconfiguration.

In the apparatus described above each of the clip arms comprises aradius section and wherein the capsule comprises a plurality ofoverhangs cooperating with the radius sections to retain the clip armsin the closed configuration when the clip arms are moved proximallywithin the capsule. Each of the clip arms also comprises stop shouldersand wherein the capsule comprises a plurality of distal folding tabscooperating with the stop shoulders to provide a first user feedbackindicative of proximal movement of the clip arms through a selectedposition in the capsule. The first user feedback includes an auralcomponent and a tactile component.

The proximal movement of the control wire beyond a point at which theclip arms are in the selected position results in separation of the yokefrom the tension member. The separation of the yoke from the tensionmember precludes returning the clip arms to the open configuration andallows further proximal movement of the yoke to release the capsule fromthe bushing.

The apparatus described further comprises a ball and socket connectionbetween the yoke and the control wire. That ball and socket connectionincludes a ball detachably coupled to a body of the control wire when atension on the control wire is at least a predetermined separationtension, the ball providing a second user feedback when separated fromthe body of the control wire.

In yet another aspect, the invention is directed to a method forhemostatic clipping comprising inserting a shaft of a clipping devicethrough a working lumen of an endoscope, wherein the shaft extends to adistal clipping assembly of the clipping device including a plurality ofclip arms and wherein a control wire extends through the shaft from theclipping assembly to a handle coupled to a proximal end of the shaft.The method also comprises manipulating the handle assembly to move acontrol wire within the shaft to move the clip arms between an open anda closed configuration, generating a first user feedback indicating adecision configuration of the apparatus, and generating a second userfeedback indicating separation of the clipping assembly from the shaft.

The method according to the present invention further comprises coveringthe shaft and the clipping assembly with an outer sheath and sliding theouter sheath proximally to uncover the clipping assembly. The clippingassembly further comprises a capsule slidably containing a yoke and atension member biasing the clip arms toward the open configuration, theyoke being coupled to the control wire and being detachably coupled tothe tension member.

The step of giving the first user feedback comprises providing aresistance force ending proximal movement of the clip arms andincreasing a resistance to a corresponding movement of the handleassembly. Also included is separating the yoke from the tension memberwhen a tension applied to the control wire after generation of the firstuser feedback is at least a first pre-selected tension. The second userfeedback is generated when a reduced diameter portion of the controlwire yields when a tension applied to the control wire is at least asecond pre-selected tension, which may be greater than the firstpre-selected tension.

The present invention has been described with reference to specificexemplary embodiments. Those skilled in the art will understand thatchanges may be made in details, particularly in matters of shape, size,material and arrangement of parts without departing from the teaching ofthe invention. Accordingly, various modifications and changes may bemade to the embodiments without departing from the broadest scope of theinvention. The specifications and drawings are, therefore, to beregarded in an illustrative rather than a restrictive sense.

The present invention has been described with reference to specificexemplary embodiments. Those skilled in the art will understand thatchanges may be made in details, particularly in matters of shape, size,material and arrangement of parts without departing from the teaching ofthe invention. For example, different shapes of the yoke, the tensionmember and the bushing may be used, and different attachments of theclip arms and control wire may be employed. Accordingly, variousmodifications and changes may be made to the embodiments withoutdeparting from the broadest scope of the invention as set forth in theclaims that follow. The specifications and drawings are, therefore, tobe regarded in an illustrative rather than a restrictive sense.

1-15. (canceled)
 16. A clip deployment apparatus insertable to locationswithin a body through an endoscope, the apparatus comprising: anelongated member extending from a proximal end to a distal end; acontrol element extending from the proximal end of the elongated memberto the distal end thereof; a bushing coupled to the distal end of theelongated member, the busing including a plurality of tabs extendingradially inward from a distal end thereof; a capsule releasablyconnected to a distal end of the bushing by a plurality of substantiallyA-shaped openings formed in a proximal end thereof, each of the A-shapedopenings receiving a corresponding one of the tabs; a clip slidablyreceived within the capsule, the clip including clip arms moveablebetween open and closed configurations; a tension member slidablyreceived within the capsule and coupled to the clip; and a yoke slidablyreceived within the capsule and removably coupled to the tension member,a first end of the yoke being releasably connected to the tension memberand a second end of the yoke being connected to the control element sothat distal movement of the control element draws the yoke, the tensionmember and the clip distally to a position in which the clip arms are inthe open configuration and proximal movement of the control elementpushes the yoke, the tension member and the clip proximally to aposition in which the clip arms are in the closed configuration.
 17. Theapparatus according to claim 16, wherein each of the clip arms comprisesa radius section and wherein the capsule comprises a plurality ofoverhangs cooperating with the radius sections to retain the clip armsin the closed configuration as the clip arms are moved proximally withinthe capsule.
 18. The apparatus according to claim 16, wherein each ofthe clip arms comprises a stop shoulder and wherein the capsulecomprises a plurality of distal folding tabs cooperating with the stopshoulders to provide a first user feedback indicative of proximalmovement of the clip arms to a selected position in the capsule at whichthe clip arms are in the closed configuration.
 19. The apparatusaccording to claim 17, wherein the first user feedback includes an auralcomponent and a tactile component.
 20. The apparatus according to claim18, wherein the tension member and the yoke are coupled to one anotherso that proximal movement of the control element after receipt of thefirst user feedback separates the yoke from the tension member.
 21. Theapparatus according to claim 20, wherein the capsule and the clip armscooperate so that, after separation of the yoke from the tension memberthe clip arms are retained in the closed configuration.
 22. Theapparatus according to claim 20, wherein the yoke includes a distalcamming surface so that, after separation of the yoke from the tensionmember, drawing the control element and the yoke further proximallybrings the camming surface into contact with the tabs to release thecapsule from the bushing.
 23. The apparatus according to claim 16,wherein the yoke and the control element are coupled to one another by aball and socket connection.
 24. The apparatus according to claim 23,wherein the control element includes a ball at a distal end thereof, theball being received within a socket formed in the yoke.
 25. Theapparatus according to claim 24, wherein the control element includes afailure location which, when subject to a predetermined tension fails toseparate the ball from a proximal portion of the control element. 26.The apparatus according to claim 25, wherein the control element isformed as a wire with the failure location constituting a reduceddiameter portion of the wire adjacent to the ball.
 27. The apparatusaccording to claim 25, further comprising a control element sheathcovering a portion of the control element including the reduced diameterportion so that, after failure of the control element, a severed end ofthe control element is enshrouded by the control element sheath.
 28. Theapparatus according to claim 25, further comprising a control elementlock mechanism which, after the control element is drawn proximally pasta predetermined point, prevents distal movement of the control elementbeyond the predetermined point.
 29. The apparatus according to claim 28,wherein the control element lock mechanism includes an abutting surfaceformed on the bushing to define the predetermined point and an abuttingsurface engaging member coupled to the control element to engage theabutting surface.
 30. The apparatus according to claim 28, wherein theabutting surface engaging member is biased to extend radially outwardfrom the control element at an angle relative thereto to an engagingposition and is radially compressible as the control element is drawnproximally through an opening with a diameter less than a radial extentof the abutting surface engaging member.